There are certain truths the NBA world has held to be self-evident since the time someone decided a piece of curved iron would work better than a peach basket as a goal.

Rookies cannot play defense.

Teenage rookies cannot and will not play defense.

European teenage rookies cannot and will not play defense, even if the fate of humanity depends upon it.

With the season still in its embryonic stage, Ntilikina, the Knicks’ 19-year-old French point guard, is going against all convention. He is actually defending, and apparently (gasp!) enjoying it.

“It was just part of developing my game in Europe,” Ntilikina said Tuesday before the Knicks faced the Hornets — with All-Star Kemba Walker and reserve Malik Monk, the guy many felt the Knicks would draft No. 8. “Me, obviously I know when you’re a rookie, you’re not as strong as the other players who got a lot of experience in the game. So you just have to be more willing to defend more, willing to stop the player. And, yeah, just do more of the work.

“But of course you have to work physically to be ready to stop stronger guys, but you can win on the court and I think that’s what I’m doing.”

Ntilikina tied a career high with eight assists and played 25 minutes in a 118-113 win against the Hornets.

The slender teen who sits behind starter Jarrett Jack has impressed in many ways and put all of it on display Sunday in the comeback win over Indiana when he played the entire fourth quarter. Ntilikina hit the 3-point shot late that gave the Knicks the lead for good. He made steals — three of them, in fact. And he showed a fearless streak that coach Jeff Hornacek absolutely loves.

Ntilikina bricked a 3-pointer. No worries. He came right back and hit the one that mattered. As so many of his teammates stressed, he grew up — a lot — in the endgame Sunday.

“We’ve seen it in practice, he’s never afraid of anything. And you saw in the game, he got us into plays, trying to put a little pressure trying to get back in the game. He wasn’t afraid,” Hornacek said. “Not only the shot that he made, a big 3, but he missed one prior to that. But there was no hesitation on shooting.

“They kicked it out to him … he caught it and shot it and didn’t think twice about it. I thought that was big because a lot of guys young, 19-year-olds miss a shot, it would be tough for them to come back and shoot another one. But he got it again and didn’t hesitate and shot it. [He was] getting us into plays as a point guard, his defense was great.”

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Oh yeah, that defense. Hornacek noted how advanced Ntilikina looks playing against pick-and-rolls. Now in recent years run pick-and-roll against the Knicks, score at will. Endlessly.

“We knew he was a good defender,” Hornacek said. “What surprised me is, again, because you see it with a lot of young players, the NBA game, a lot of pick-and-rolls. The pick-and-roll is probably one of the hardest things to guard from that point-guard spot.

“I’ve been pleasantly surprised that he doesn’t have a huge problem with that. He fights over them. I think his length probably helps him get over those screens. If we decide to switch, he’s got the size and length of arms where it’s hard for guys to throw to maybe a roller. The surprising part is how well he can get over screens.”

Ntilikina has been welcomed big-time at the Garden. A nearby building — until very recently — has been adorned with his Godzilla-size likeness. But it was removed in recent days.

“It was very cool to have that kind of a billboard here,” Ntilikina said. “But my main thing is on the court, so that’s what I’m thinking about.”